I decided I wanted a dyno

[Flyinhillbilly]

A bit scary is kind of what I do

You hit the nail on the head with the "simple enough to replicate" statement. I'm hoping this works well enough that I can make a how to series so people who think they need one can build their own dynos.
When this version is done I'm going to deliberately try to blow it up.









Also I'm hoping for a buttload of views and subscribers .

 

[chancer]

You Gotta love Sid! LOL
Here is what you need, this is great, ...But it is not available!

I dunno I just found that a little funny. Good humor!

 

[Flyinhillbilly]

Anything Tesla related, I'm on board with. Albert Einstien called him "the smartest man ever born"



But I'm poor, and have to build my stuff out of junk.

 

[itsid]

alright.. but one airbubble and that pressure isn't going to play nice...
liquid as being incompressable I see no real danger, a busted tube, a mess in the shop.. who cares..
air propelled oil speeding at your face and the story gets into a totally different level of thrill.
So at least be cautious

I figured you'd target the replicable part.. and if that works more or less reliably, that is THE best attempt I've seen
(small partcount, lightweight, no utterly expensive machinery required)

The DYNAMIC portion of dyno is still a bit vague with a read out like yours,
a cheap digital torque meter around here costs about'ish fifty bucks.. the cheapest one I can find WITH external R/O and plotting capabilities is ten times that already.

But at worst you'd need to record the display as a video and draw yourself to save some money.

but I just wanted to mention something else...
How about (for testing purpose)
attach the engine with a v-belt and two pulleys..
first you could set up a gear ratio to match your torque meter at it's sweet spot,
second, thanks to being a rubber belt there will be next to no vibration
and third.. again thanks to being non toothed.. stalling is not really a thing any longer;
before it stalls, the belt will very likely just slip and burn.

Sure enough, a belt is not 100% effective in transfering power for the very same reasons as above but for a quick test it should at least give you a glance, right?

'sid

[EDIT]
I'm slower than I thought these days..
Well Eric not commercially available doesn't mean you cannot find one or get one..
or MAKE one!
It's really simple anyone with a mill will be able to make one.
(a CNC router would work even better I must admit with all the computer precision and such)

Anyways, nothing too fancy really.

from junk... that's at least a challenge then, right?
I mean just think about it.. one would make a full small engine dyno from junk parts... insane!

 

[Flyinhillbilly]

Your spot on. The reason I'm going to try to blow it up is that if I'm going to put a how to out there, I want to be sure people won't get hurt by it. I'll probably build some guards before the torture test for obvious reasons. From what I understand, if I add a tach and video the pull with torque and RPM I can then plot my horsepower with a calculator and some graph paper. Hp is just
Torque x RPM/5252.1

 

[mckutzy]

On that vid I posted, the guys have a hydraulic motor and a jerry can for reservoir, im guessing it is vented, or at least there is a significant amount of fluid in the system the with the operation at full tilt, there isnt much opportunity for it to get air into the system.....kinda self bleeding on the initial movements at low speed....

I guess one(you in the case FH) could fab a blast shield for the pump, if you used good hydraulic lines for the rest of the operation....

In my way of picturing it in operation.... You might need it to be a 2 man job.... a throttle man and the load operator.

 

[chancer]

Would it be possible to use a vacuum pump, To evacuate all the air first. Then add the oil.
Eliminating the risk of air bubbles?

 

[mckutzy]

I guess one could..... but existing hydraulic systems dont need to have the lines vac'd... they just properly prime the system, and the breather vent is on the tank...
If he wanted to get fancy... he could put a check valve...... but then he'd have a pressurized system in idle....

Edit again: here's what I was trying to get at...

http://hydraulicspneumatics.com/hydraulic-pumps-motors/pop-cavitation-bubble-hydraulic-systems

 

[Flyinhillbilly]

I just remembered that I have this. 6+ gallons. Problem solved.

 

[Flyinhillbilly]

from junk... that's at least a challenge then, right?
I mean just think about it.. one would make a full small engine dyno from junk parts... insane!

That oil pump is a takeout from an engine I'm building aka junk. Any automotive machine shop would give you two or three if you tell them what you're doing.

Just sayin'

 

[mckutzy]

With that being said, you could probably get a bucket or two of oil that is not too badly used, that you could filter enough of the crap out.... that could be used in your experiment here.....Mainly from all free or cheaply acquired stuff..

 

[Flyinhillbilly]

We do oil changes where I work. Good used oil is a non issue.

 

[mckutzy]

This is so cool....

 

[Flyinhillbilly]

http://m.hydraulicspneumatics.com/hydraulic-pumps-motors/pop-cavitation-bubble-hydraulic-systems

That was a good read, thanks.
As far as the hydraulic line goes, everything under pressure is double braid gates hydraulic hose. From the pump to the valve is the only part under pressure. Everything else is feed or return.

 

[itsid]

Your spot on. The reason I'm going to try to blow it up is that if I'm going to put a how to out there, I want to be sure people won't get hurt by it. I'll probably build some guards before the torture test for obvious reasons. From what I understand, if I add a tach and video the pull with torque and RPM I can then plot my horsepower with a calculator and some graph paper. Hp is just
Torque x RPM/5252.1

Well with your artificial units that's a convenient shortcut, yes.
if it's precise... I can't tell (never cared much about how many decimals you use to improperly calculate power more or less precisely )
But yes, that's what I meant.. two readings rpm and torque and you can go from there step by step manually..
reading the values at any given video frame. (or say 10 )

That oil pump is a takeout from an engine I'm building aka junk. Any automotive machine shop would give you two or three if you tell them what you're doing.

Just sayin'

I know.. you told us... irony...

"You can build a dyno from junkparts.. you'll surely be able to build a tesla valve too if you wrap your head around it for a while."

is what I intended to say

'sid

 

[Flyinhillbilly]

Really it doesn't matter how accurate it is. It will give me a tangible reading to measure improvements by, it's not like I'm trying to sell this.
I'm pretty set on using this oil pump because they're widely available, cheap, and I want to make something anyone can do.

 

[chancer]

Really it doesn't matter how accurate it is. It will give me a tangible reading to measure improvements by

See this is an attitude I like. You do not need to Brag about...
"I got 11. HP out of my 5Hp Briggs" ..."Blah blah blah."

This way you know which mods are the best bang for your buck.
Which direction your going, What is not worth doing and what is.

You can easier see and say this was a 11% "Improvement" or "that did nothing."
No need to have a Male Chicken measuring contest.
Just know what you are doing.
Beautiful!

 

[Flyinhillbilly]

http://www.enginelabs.com/news/video-test-shows-top-fuel-nitro-engine-makes-over-11000-horsepower/
Pretty cool write up on an inline torque sensor.

 

[Flyinhillbilly]

Got tanked
Flooded sump feed, and the return goes down a tube to the bottom of the tank, and the cap is vented. I think I have all my bases covered here. I think V2.0 will use a steel boat gas tank so that I can just weld merchant couplings to it to make it easier. Also, I think V2.0 may end up being a chassis dyno provided this works out.



I'm heading for my dad's this afternoon and will be out of town with no internet service for at least a couple of days. I'll get going on this again when I get back.

 

[bob58o]

So I've been wondering if you could use an under-powered engine on a generator as a dyno?

I'm sure a car alternator wouldn't load a 6.5 HP engine enough, but a 6500W generator might????
Sorry for Jack, just been on my mind.